1. Field of the Invention
The present invention relates to a ladder with anti-deformed side rails, particularly to a ladder, which has inner bushings of certain sizes inserted in the feet of the side rails to prevent the side rails from undergoing permanent deformation.
2. Description of Related Art
For mounting rungs of a metal ladder on the side rails thereof, the rungs extend beyond the side rails, held therein by retaining protrusions. The rungs have bend back ends instead of bolts, nails, supporting brackets or other conventional fasteners. This structure allows for light and inexpensive ladders, which are convenient to use. However, during use of such a ladder large loads may rest on the feet of the side rails. The side rails are thus deformed and may even break. To overcome this deficiency, ladders with a additional bottom bar 8 have been designed, as shown in FIG. 6. The bottom bar 8 enhances stability of the ladder. However, the bottom bar 8 is fixed to the side rails by bolts or nails, which tend to loosen, reducing stability of the ladder. Furthermore, since the bottom bar 8 extends considerably beyond the side rails, the ladder is inconvenient to store and to transport, and production cost is high.